摘要:

SUMMARY1Using sites from the Upper Rhône River, France, as an example, the objective of this paper is to identify the essential elements needed to test current ecological theories with previously collected data. Procedures developed may enable other groups to design comparable research strategies for syntheses of long‐term studies of ecological systems.2Because of the high number (more than 200) and turnover of researchers, the long study period (about 17 years), the evolution of research methods and interests, and the diverse systematic groups that were considered (from micro‐organisms to birds), the data available for a synthesis were quite heterogeneous. The application of a ‘fuzzy coding’ technique allowed such disparate information to be structured for analysis.3The habitat templet concept and the patch dynamics concept were selected for analysis with existing data on the Upper Rhône because theories, such as these, that link ecological responses to habitat templets are a focus of current ecological debate and potentially may serve as a general tool for ecologically orientated river management.4A preliminary trial to structure the existing knowledge, to identify (and manage) gaps in it, and to create and apply the analytical tools in a way that predictions from theory could be tested was an essential element in the design of this project.5Predictions derived from the theoretical concepts had to match the format of the available information on the Upper Rhône; potential bias was avoided by having a priori predictions developed by previously uninvolved colleagues.6Synthesis of the long‐term study of the Upper Rhône in the context of concurrently developed ecological theory required, at times, an unconventional research strategy. Hence, the generation of hypotheses and methods, the presentation of results, and consequently the discussions in papers of this special issue ofFreshwater Biology(Statzner, Resh&Dolédec, 1994) represent an innovative approach to testing eco

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1994.tb01739.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

SUMMARY1This paper focuses on the premise that the habitat provides the templet upon which evolution forges characteristic species traits. Alternative hypotheses are that there are historic and phylogenetic constraints on the match between organism and environment.2In our analysis of river systems, as one dimension of the templet we choose temporal heterogeneity and assume some relationship between this and the frequency of disturbance. The second dimension is spatial heterogeneity in the physicochemical environment and we pay particular attention to the way such variation can ameliorate the influence of disturbances through the provision of refugia.3We derive predictions about the traits of species, including size, generation time, reproductive tactics, body form, mobility and potential for regeneration, that are likely to occur in particular regions of the two‐dimensional templet. We also present predictions about community‐level characteristics such as number of species per resource category and total species richness. The general predictions are intended to apply to a wide range of plants, micro‐organisms and animals, provided the measurements have been made at a scale appropriate to them.4Hypotheses can be tested by comparing traits predicted for particular habitats, whose spatial and temporal heterogeneity have been quantified, with those actually observed. If the fit turns out to be good, we will be able to conclude that the habitat templet approach offers a sound framework within which to pose questions in river ec

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1994.tb01740.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

SUMMARY1Methods used for the study of species–environment relationships can be grouped into: (i) simple indirect and direct gradient analysis and multivariate direct gradient analysis (e.g. canonical correspondence analysis), all of which search for non‐symmetric patterns between environmental data sets and species data sets; and (ii) analysis of juxtaposed tables, canonical correlation analysis, and intertable ordination, which examine species–environment relationships by considering each data set equally. Different analytical techniques are appropriate for fulfilling different objectives.2We propose a method, co‐inertia analysis, that can synthesize various approaches encountered in the ecological literature. Co‐inertia analysis is based on the mathematically coherent Euclidean model and can be universally reproduced (i.e. independently of software) because of its numerical stability. The method performs simultaneous analysis of two tables. The optimizing criterion in co‐inertia analysis is that the resulting sample scores (environmental scores and faunistic scores) are the most covariant. Such analysis is particularly suitable for the simultaneous detection of faunistic and environmental features in studies of ecosystem structure.3The method was demonstrated using faunistic and environmental data from Friday (Freshwater Biology18, 87‐104, 1987). In this example, non‐symmetric analyses is inappropriate because of the large number of variables (species and environmental variables) compared with the small number of samples.4Co‐inertia analysis is an extension of the analysis of cross tables previously attempted by others. It serves as a general method to relate any kinds of data set, using any kinds of standard analysis (e.g. principal components analysis, correspondence analysis, multiple correspondence analysis) or between‐class and wi

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1994.tb01741.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

SUMMARY1We present an unconventional procedure (fuzzy coding) to structure biological and environmental information, which uses positive scores to describe the affinity of a species for different modalities (i.e. categories) of a given variable. Fuzzy coding is essential for the synthesis of long‐term ecological data because it enables analysis of diverse kinds of biological information derived from a variety of sources (e.g. samples, literature).2A fuzzy coded table can be processed by correspondence analysis. An example using aquatic beetles illustrates the properties of such a fuzzy correspondence analysis. Fuzzy coded tables were used in all articles of this issue to examine relationships between spatial‐temporal habitat variability and species traits, which were obtained from a long‐term study of the Upper Rhône River, France.3Fuzzy correspondence analysis can be programmed with the equations given in this paper or can be performed using ADE (Environmental Data Analysis) software that has been adapted to analyse such long‐term ecological data. On Macintosh AppleTMcomputers, ADE performs simple linear ordination, more recently developed methods (e.g. principal component analysis with respect to instrumental variables, canonical correspondence analysis, co‐inertia analysis, local and spatial analyses), and provides a graphical display of results of these and other types of analysis (e.g. biplot, mapping, modelling curves).4ADE consists of a program library that exploits the potential of the HyperCardTMinterface. ADE in an open system, which offers the user a variety of facilities to create a specific sequence of programs. The mathematical background of ADE is supported by the algebraic model known as ‘dual

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1994.tb01742.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

SUMMARY1This paper develops a framework of spatial and temporal variability for a habitat typology of the Upper Rhône River (France) and its alluvial floodplain that is based on about 17 years of data collection and analysis. The aim was to provide a scale of spatial‐temporal variability for river habitat templet predictions on trends in species traits and species richness.2In developing this framework, eight physical‐chemical variables were available and could be considered for twenty‐two habitat types: seventeen superficial (surface) and five interstitial (0.5 m below the substrate surface). These habitat types were selected in two areas (Jons and Brégnier‐Cordon) after geomorphological considerations and because of differences in their biological characteristics.3The data sets used were processed by a ‘fuzzy coding’ method using, for each variable, the frequency distribution (by modalities = categories) of all measurements and monthly means over an annual scale. Two tables were produced; the first corresponded to an expression of the total variability, and the second represented an evaluation of the temporal variability.4Each of these tables was analysed by correspondence analysis, which provided factorial scores that were used to calculate, by habitat type and by variable, a total variability and a temporal variability in terms of cumulated variability of factorial scores for the eight physical–chemical variables. The rationale in describing variability from these two tables is that total variability equals temporal variability plus spatial variability. The spatial variability was then determined by the difference between total and temporal variability. From this procedure, a positioning of the twenty‐two habitat types on the spatial and temporal variability axes was obtained.5The estimate of spatial variability did not consider any error term that may have occurred in the above model; it was then tested by an independent assessment of the spatial variability using thirteen variables in nine major habitat types. A high correlation between the two ways of assessing spatial variability (r = 0.85, P<0.004) underscored the reliability of the spatial variability that was calculated previously.6The river habitat templet obtained for the Upper Rhône and its alluvial floodplain appears to be appropriate to test the predictions on patterns of species traits and species richness in the framework of spatial and te

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1994.tb01743.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

SUMMARY1This paper summarizes twenty years of ecological research on aquatic oligochaetes of the Upper Rhône River and its alluvial floodplain (France). Species traits of fifty species of the ninety taxa recorded from two areas Gons and Brégnier‐Cordon) were used to examine the relationships among species traits, habitat utilization of these species, whether a relationship exists between species traits and habitat utilization, and the applicability of predictions from the river habitat templet and the patch dynamics concept in the framework of spatial and temporal habitat variability. We used fourteen habitat types and sixteen species traits in this analysis.2When examined by correspondence analysis, species traits separate the Naididae (with a higher potential for reproduction, small size, high mobility, and opportunistic diet) from all other families.3Habitat utilization by oligochaetes demonstrates two gradients: a vertical gradient that arranges species by their affinity for interstitial habitats (stygophily) and a transversal gradient that arranges them by their affinity for main channel habitats (rheophily).4No significant relationship was found between species traits and habitat utilization in a co‐inertia analysis.5Trends observed for species traits within the framework of spatial‐temporal habitat variability show only minor agreement with predictions of the river habitat templet.6Species richness is generally higher in superficial and interstitial habitats that are permanently connected with the main channel, and peaks in the superficial parapotamons (backwaters that are permanently connected with the main channel) characterized by intermediate levels of spatial as well as temporal variability; this pattern only partially fits with predictions of the patch dynamics

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1994.tb01744.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

SUMMARY1Ostracods occurring at two sections of the Upper Rhône River, France, were examined to determine relationships among species traits, habitat utilization, the relationship between species traits and habitat utilization, and trends in species traits and species richness in the context of spatial and temporal variability of habitats. Twenty regularly sampled species were used in this study and fifteen species traits were considered.2Throe groups can be distinguished according to their species traits: group 1 has species of mixed sizes with high reproductive rates, short life span, spherical shape, long swimming bristles, low thigmotactism, and high resistance to desiccation; group 2 has medium‐sized species with low reproductive rates, long life span, low or no tolerance to desiccation, geometric (trapezoidal, triangular) or streamlined carapace shape, no swimming bristles, and a strong thigmotactism; group 3 has the largest species with parthenogenetic reproduction, medium‐sized swimming bristles, and flattened or cylindric carapace shape.3Ostracod habitat utilization segregates the superficial and interstitial habitats along a gradient from the main channel to the abandoned arms and to the temporary waters.4The co‐structure (= relationship) between species traits and habitat utilization indicates that the species use particular habitats with a particular set of species trait modalities. Species with long life spans, late maturity, low fecundity, and low migratory ability are restricted to the interstitial habitats; the epigean species with long life spans, large size, and parental care are more abundant in permanent flowing and standing surface waters; the epigean species with short life spans, high migratory ability, and high tolerance to desiccation are more abundant in temporary ponds.5The analyses of the distribution of the species traits in a river habitat templet of spatial and temporal variability emphasized that the main disturbance structuring the Rhône River ostracod assemblage is desiccation.6Of the trends predicted for species traits in the framework of the river habitat templet, five (size, body form, attachment, reproductive technique, and mobility) are clearly opposite for ostracods (because the predictions were mainly established for flood‐related disturbances) but four (life span, number of reproductive cycles per year, age at first reproduction, and desiccation tolerance) are in agreement.7No trends in ostracod species richness in the framework of spatial–temporal habitat variability w

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1994.tb01745.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

SUMMARY1Ephemeroptera and Plecoptera in two sites of the Upper Rhône River (France) were examined using multivariate analyses to determine: (i) relationships among seventeen species traits; (ii) habitat utilization of the fifty‐five species present; (iii) the relationship between species traits and habitat utilization; (iv) trends of species traits and species richness in a framework of spatial and temporal habitat variability.2The species traits having the highest correlation ratios correspond to reproduction or life cycle, behavioural, and morphological characteristics. According to their traits, species of Baetidae, Caenidae, and Leptophlebiidae (Ephemeroptera) are opposite species of Perlidae and Perlodidae (Plecoptera).3The distribution of species in thirteen habitat types of the Upper Rhône River floodplain demonstrates a transverse gradient from the main channel to the oxbow lakes. Plecoptera are restricted to the different main channel habitats; in contrast, Ephemeroptera families have a broader distribution with Baetidae and Leptophlebiidae occurring in most floodplain habitats.4Plecoptera exhibit a significant relationship between species traits and habitat utilization but no relationship is evident for Ephemeroptera. Baetidae use many habitat types and have diverse species traits; in contrast, Leptophlebiidae, Heptageniidae, and Caenidae use many habitat types but each family has a rather uniform set of traits.5Trends in species traits were significantly related to both the spatial and temporal variability of habitats. Considering only temporal variability, the distribution of species trait modalities (= categories) corresponded well to predictions on trends in the river habitat templet for ‘minimum age at reproduction’ and ‘potential longevity’, and in general for ‘descendants per reproductive cycle’, ‘reproductive cycles per year’, ‘potential size’, and ‘body flexibility’ trends in six other traits did not match predictions.6No trends in species richness were evident in spatial–temporal fra

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1994.tb01746.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

SUMMARY1To test predictions of the river habitat templet and the patch dynamics concept, trends in species traits and species richness of aquatic beetles were related to the spatial‐temporal variability of eighteen habitat types in the alluvial floodplain of the French Upper Rhône River. One hundred and twenty species of beetles were used in this analysis.2The basic information was obtained either from the literature (for most of the species traits) or from observations made at approximately 500 sampling sites in the Brégnier‐Cordon and Jons sections over the past 19 years (for habitat utilization). This information was structured by a fuzzy coding technique and examined by ordination analyses.3Analyses of the relationships among nineteen species traits revealed a clear distinction according to traits such as body form (for adults), functional feeding type and food (adults and larvae), attachment to the substrate and dissemination potential (adults and larvae), and patterns of aquatic and/or terrestrial life of adults and larvae. Species traits such as number of descendants per reproductive cycle, and number of reproductive cycles per year or per individual showed less contrast, because these traits are rather homogeneous in aquatic beetles.4Analyses of the habitat utilization by the aquatic beetles revealed a vertical gradient that separates interstitial from superficial habitats, and a transverse gradient for the superficial habitats, which extends from the main channel towards permanent oxbow lakes and temporary waters.5The significant relationship betweeen species traits and habitat utilization demonstrates that most beetle species use a particular set of habitat types with a particular set of species trait modalities.6Species traits of aquatic beetles are homogeneous but evidently very successful and are adapted to many potential conditions of spatial–temporal variability. Because of this homogeneity, observations on aquatic beetles do not support trends of traits in the framework of spatial–temporal variability predicted from the river habitat templet.7The observed species richness of aquatic beetles is low in habitat types with a low spatial–temporal variability, increases as spatial variability increases, and tends to be highest at intermediate temporal variability. This pattern matches predictions of the patch dynam

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1994.tb01747.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

SUMMARY1For Trichoptera occurring in two sites of the Upper Rhône River (France) we examine: (i) relationships among species traits; (ii) habitat utilization of Trichoptera species; (iii) the relationship between species traits and habitat utilization; (iv) trends of species traits in the framework of spatial–temporal habitat variability to test predictions of the habitat templet concept; and (v) trends of species richness in the framework of spatial–temporal habitat variability to test predictions of the patch dynamics concept.2Of the sixteen species traits selected, twelve have high correlation ratios for the seventy‐five species used in this analysis; these traits are related to behavioural, morphological, or physiological aspects. Traits related to reproduction or life cycle have lower correlation ratios.3An ordination by species traits separates the five main families into three groups: (i) Hydropsychidae and Polycentropodidae; (ii) Hydroptilidae; and (iii) Leptoceridae and Limnephilidae. An ordination of the habitat utilization of the species in ten habitats indicates that the Hydropsychidae occur preferentially in the main channel, Hydroptilidae, Polycentropodidae, and Limnephilidae occur in backwaters or oxbow lakes, and the Leptoceridae are ubiquitous.4The Hydropsychidae exhibit a relationship between species traits and habitat utilization, i.e. they use similar habitat types with similar species traits. The species traits of the other four families are similar but their habitat utilization is quite different.5The Hydropsychidae occur in lowest spatial–temporal variability habitats and Limnephilidae in the highest. Therefore, net spinners and filterers are characteristic of habitats with a low spatial–temporal variability, whereas shredders and case makers using plant material are characteristic of habitats with high spatial–temporal variability. The trends in species traits show little agreement with trends predicted from the river habitat templet.6Trends of species richness in the framework of spatial and temporal variability do not follow the predictions of the patch dynamics concept because richness is similar in all superficial habitats. This implies that each habitat, in spite of large differences in their spatial and temporal variability, offers Trichoptera a similar but limited number of ecolo

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1994.tb01748.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY